Wire bonding technique for integrated circuit board connections

Abstract

A method is provided for connecting a chip die to a circuit board with a capillary dispenser to deposit gold. The method includes forming a first bond by depositing gold from the dispenser to a board pad on the circuit board; forming a second bond by depositing the gold from the dispenser to a die pad on the chip die; extruding a filament of the gold by the dispenser in a normal direction from the second bond; rotating the filament laterally away from the first bond along a first radius; extruding the filament while rotating the filament towards the first bond along a second radius larger than the first radius; and forming a third bond by depositing the gold on the first bond to form a third bond.

What is claimed is: 
     
       1. A method for connecting a chip die to a circuit board with a capillary dispenser to deposit gold, said dispenser forming a free air ball (FAB) at a depositing tip, said method comprising:
 forming a first bond by depositing the gold at the FAB from the tip to a board pad on the circuit board; 
 forming a second bond by depositing the gold at the FAB from the tip to a die pad on the chip die; 
 extruding a filament of the gold by the tip in a normal direction from said second bond; 
 rotating said filament laterally away from said first bond along a first radius; 
 extruding said filament while rotating said filament towards said first bond along a second radius; and 
 forming a third bond by depositing the gold at the FAB by the tip on said first bond to form said third bond. 
 
     
     
       2. The method according to  claim 1 , wherein said second radius is larger than said first radius. 
     
     
       3. The method according to  claim 1 , wherein said filament has diameter between 0.2 μm to 30 μm.